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Arrow-headed Rattle-box (Crotalaria sagittalis)


Life history

Species overview

Arrow-headed Rattle-box (Crotalaria sagittalis), a State Special Concern plant, is found apparently in dry prairie areas, but habitat requirements are not well-understood; it has also been documented along a sandy lakeshore. Blooming occurs late July through early September; fruiting occurs early August through late September. The optimal identification period for this species is late July through late August.

Synonyms: Crotalaria fruticosa, Crotalaria sagittalis var. blumeriana, Crotalaria sagittalis var. fruticosa, Crotalaria sagittalis var. oblonga

Identification

  • Distinguishing characteristics: Distinguished from other members of the legume family by its combination of simple leaves and yellow petals.
  • Flower characteristics: Yellow pea-like flowers with a large upper petal above, two small lateral petals, and a small keel below.
  • Fruit characteristics: Oblong, inflated, 1.5 to 3 cm long seed pods.
  • Leaf characteristics: 3 to 8 cm long x 1.5 cm wide, simple (not compound as is typical for the pea family), lance-shaped to linear leaves, hairy on both sides; sessile (attached directly to the stem without a petiole).

Phenology

  • Blooming phenology: late July through early September
  • Fruiting phenology: early August through late September
  • Optimum time to identify: late July through late August

Other

  • Growth form: Forb-erect
  • Vegetative reproduction:
  • Life cycle: Annual
  • Comments: Associated Species: Bouteloua curtipendula, B. hirsuta, Sorghastrum nutans, Polygala verticillata, Ambrosia artemisiifolia, Andropogon gerardii, Euphorbia corollata.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Arrow-headed Rattle-box (Crotalaria sagittalis). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.


Documented locations of Crotalaria sagittalis in the Natural Heritage Inventory Database as of March 2012.

Summary Information
State StatusSC
Federal Status in Wisconsinnone
State RankS1
Global RankG5
Tracked by NHIY

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

  • Habitat description: Found apparently in dry prairie areas, but habitat requirements are not well-understood; it has also been documented along a sandy lakeshore.
  • Soils: Dry and sandy soils.

Natural communities

This table lists the natural communities that are associated with Arrow-headed Rattle-box. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Natural communities score
Dry Prairie 3
Inland Beach 2

Ecological landscapes

This table lists the ecological landscape association scores for Arrow-headed Rattle-box. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Map of the Ecological Landscapes of Wisconsin.

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

  • Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.
  • Avoid broadcast spraying of herbicides; use care with spot spraying.
  • Avoid locating landings, staging areas, or access routes in open sandy areas dominated by native grasses.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

  • Maintain and restore open habitat through selective clearing and brushing.
  • Avoid disturbance to shorelines and the forest-beach interface.
  • Prescribed burns and/or brushing may be beneficial (dependent on local site conditions).

Photos


Arrow-headed Rattle-box  [Photo #1822]

Specimen scanned by the Wisconsin Herbarium, Madison, WI.

Photo ©  Wisconsin Herbarium.

Arrow-headed Rattle-box  [Photo #1823]

Specimen scanned by the Wisconsin Herbarium, Madison, WI.

Photo ©  Wisconsin Herbarium.

Arrow-headed Rattle-box  [Photo #1824]

Specimen scanned by the Wisconsin Herbarium, Madison, WI.

Photo ©  Wisconsin Herbarium.

Arrow-headed Rattle-box  [Photo #23862]

Photo © ASU Vascular Plant Herbarium .


Support for Wisconsin's rare plant information has been provided by the Division of Forestry, the Endangered Resources Fund and the Wisconsin Rare Plant Preservation Fund. To donate, visit the Natural Resources Foundation of Wisconsin [exit DNR].

Last revised: Tuesday, October 07, 2014
Southwest Savanna Southern Lake Michigan Coastal Western Coulees and Ridges Southeast Glacial Plains Central Sand Hills Central Lake Michigan Coastal Central Sand Plains Northern Lake Michigan Coastal Northern Lake Michigan Coastal Northeast Sands Western Prairie North Central Forest Northern Highlands Northwest Lowlands Northwest Sands Northwest Lowlands Superior Coastal Plains Forest Transition